THE GENERAL STRESS STRAIN RELATION OF SOILS INVOLVING THE ROTATION OF PRINCIPAL STRESS AXES

In the light of matrix theory, the charader of siress increment which causes the rotation of principal stress axes is analysed and the general stress increment isdecomposed into two parts: coaxial part and rolational part. Based on these, thecomplex three dimensional (3-D) problem involving the rotation of principal stress axesis simplified to the combination of the 3-D coaxial model and the theory about pureroation of principal stress axes that is only around one principal stress axes. Thedifficulty of analysis is reduced significantly. The concrete calculating method ofgeneral 3-D problem is provided and other applications are also presented.